Aerodynamic Optimisation of an Aeroengine Bypass Duct OGV-Pylon Configuration

Tschirner, Thomas; Pfitzner, Michael; Merz, Ru ̈diger

doi:10.1115/gt2002-30493

Cited by 4 publications

(3 citation statements)

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“…The contours of Mach number at three sections of the intake are illustrated in figure (6). The Mach number is maximum near the casing and decrease in the radially inward direction upstream the fan nose; figure (6-a).…”

Section: Resultsmentioning

confidence: 99%

“…The evaluation of the performance of the fan blades also requires an accurate prediction of the turbulent boundary layer and of a possible separation of the blade boundary layer. Therefore it was decided to use the Spalart-Allmaras model of turbulence which is known to be one of the best turbulence models for the prediction of fan aerodynamics and includes a good low-Reynolds-number model [6]. The Spalart-Allmaras model is relatively simple one-equation model that solves modeled transport equations for the kinematic turbulent viscosity.…”

Section: The Spalart-allmaras Model Of Turbulencementioning

confidence: 99%

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Three-Dimensional Flow in a Transonic Axial Flow Fan of a High Bypass Ratio Turbofan Engine

El-Azim

Gobran

Hassan

2011

International Conference on Aerospace Sciences and Aviation Tec

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The present study deals with the air flow through an axial flow transonic fan blades, found in high bypass turbofan engines. Examples are CF-6, RB211 and GE90 turbofan engines. The fan has a wide chord, highly twisted blades of large span with a mean hubto-tip ratio of about 0.404. The blades are tapered with its maximum chord at the tip radius. Moreover, these twisted blades have slight reduction in its maximum thickness from hub to tip.Consequently, the flow field is a three dimensional viscous compressible. The engine intake together with the fan resemble the case studied here. The computational domain includes two periodic merged sectors at a central angle of 360 degrees divided by the number of blades (38). The first sector is stationary, which represents the intake domain, while the second is rotating, which represents the fan domain that comprehending one blade. This is an effective way of reducing the calculation time and speeding up the iterations. The investigated model (Intake and fan blade) dimensions and configuration are identified by measuring real dimensions of CF-6 engine fan module. The FLUENT solver employing the Spalart-Allmaras turbulence model is used to solve the flow field in both the intake and fan. The program results represent the variation of the flow characteristics (pressure, temperature, Mach number, etc) in the flow field at the design condition (cruise conditions; namely, 11000 m altitude, 0.85 Mach number and 3674 rpm fan speed). The fan performance map was also predicted for a range of percentage fan corrected speed from 60% to 110%. KEY WORDSTransonic flow, Axial fan, High bypass turbofan engine, Intake, swept blades.

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Section: Resultsmentioning

confidence: 99%

Section: The Spalart-allmaras Model Of Turbulencementioning

confidence: 99%

Three-Dimensional Flow in a Transonic Axial Flow Fan of a High Bypass Ratio Turbofan Engine

El-Azim

Gobran

Hassan

2011

International Conference on Aerospace Sciences and Aviation Tec

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“…The shape and thickness of the pylon cross-sections could potentially be modified to alleviate the rotor back pressure distortion generated by the pylon potential field [84].…”

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confidence: 99%

Ultra-Short Nacelles for Low Fan Pressure Ratio Propulsors

Peters¹,

Spakovszky²,

Lord³

et al. 2014

Volume 1A: Aircraft Engine; Fans and Blowers

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This thesis addresses the uncharted inlet and nacelle design space for low pressure ratio fans for advanced aeroengines. A key feature in low fan pressure ratio (FPR) propulsors with short inlets and nacelles is the increased coupling between fan and inlet. The thesis presents an integrated fan-nacelle design framework, combining a spline-based tool for the definition of inlet and nacelle surfaces with a fast and reliable body-force-based approach for the fan rotor and stator blade rows. The new capability captures the inlet-fan and fan-exhaust interactions and the flow distortion at the fan face and enables the parametric exploration of the short-inlet design territory. The interaction of the rotor with a region of high streamwise Mach number at the fan face is identified as the key aerodynamic mechanism limiting the design of short inlets. The local increase in streamwise Mach number is due to flow acceleration along the inlet internal surface coupled with a reduction in effective flow area. For a candidate short-inlet design with inlet length to fan diameter ratio L/D = 0.19, the streamwise Mach number at the fan face near the shroud increases by up to 0.16 at cruise and by up to 0.36 at off-design conditions relative to a long-inlet baseline propulsor with L/D = 0.5. As a consequence, the rotor locally operates close to choke, resulting in fan efficiency penalties of up to 1.6 % at cruise and 3.9 % at off-design. For inlets with L/D < 0.25, the benefit from reduced nacelle drag is offset by the reduction in fan efficiency, resulting in propulsive efficiency penalties. Based on a parametric inlet study, the recommended inlet L/D for engine propulsive efficiency benefits is suggested to be between 0.25 and 0.4. A candidate design with L/D = 0.25 maintains the cruise propulsive efficiency of the baseline case without jeopardizing fan and LPC stability at off-design conditions. On the aircraft system level, fuel burn benefits are conjectured to be feasible due to the reductions in nacelle weight and drag compared to an aircraft powered by the long-inlet baseline propulsor.

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PADRAM: Parametric Design and Rapid Meshing System for Turbomachinery Optimisation

Shahpar

Lapworth

2003

Volume 6: Turbo Expo 2003, Parts a and B

112

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A parametric design system suitable for inclusion in an automatic optimization process is presented. The system makes use of a multi-block structured grid generation system specially designed for the rapid meshing of two-dimensional, quasi-three-dimensional, and three-dimensional single passage as well as multi-passage, multi-row turbomachinery blades. Full annulus viscous meshes of the order of five to ten million mesh points for the complete bypass assembly of the low pressure compression (LPC) system can be generated in a matter of minutes. PADRAM offers a major new design capability where the optimisation of multi-passage three-dimensional blades and its circumferential pattern is done simultaneously in one system. Successful usage of PADRAM in a number of design, optimisation and analysis applications has recently been demonstrated and reported herein.

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Aerodynamic Optimisation of an Aeroengine Bypass Duct OGV-Pylon Configuration

Cited by 4 publications

References 0 publications

Three-Dimensional Flow in a Transonic Axial Flow Fan of a High Bypass Ratio Turbofan Engine

Three-Dimensional Flow in a Transonic Axial Flow Fan of a High Bypass Ratio Turbofan Engine

Ultra-Short Nacelles for Low Fan Pressure Ratio Propulsors

PADRAM: Parametric Design and Rapid Meshing System for Turbomachinery Optimisation

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